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View Full Version : Pulling Motor. Thoughts?



95_XR7
01-03-2013, 10:25 PM
What I have is Julian Miller's old AR'ed Supercoupe.
I finally have time to pull the motor and am currently working on it, but in the meantime am curious as to what all of you think is wrong with it.

According to Julian (and hopefully I remember right.), there was severe blowby, instant fouling of the plugs on the motor after a pretty new rebuild. Well, I have started to tear it apart.

-Currently, there was a fairly large amount of oil at the bottom of the intercooler. It literally poured out. I know some is normal but this definitely wasn't normal.

-There is a good 1/4in of oil sitting within the intake manifold.

-Oil was drained and looked good. Not milky or discolored, nor did it have a strong fuel smell.

-Coolant was drained and looked brand new.

-Lots of nasty deposits on the waterpump, upper and lower radiator hoses.


My dad thinks its lifted heads, and possibly piston rings are jacked up. Whats your thoughts.

-Corey

90sc35thann
01-03-2013, 10:34 PM
If the head lifted you would have coolant in the oil. That doesn't mean you don't have faulty rings, cracked piston, worn out cylinder, etc.

95_XR7
01-03-2013, 10:36 PM
If the head lifted you would have coolant in the oil. That doesn't mean you don't have faulty rings, cracked piston, worn out cylinder, etc.

See and I was thinking that, but from what I looked up on here, plenty of people have lifted the heads while using the MLS gaskets and had LITTLE to no coolant sitting in with the oil. It was also using ARP head studs.

Btw, I forgot to mention. The motor had been rebuilt at one time. From my understanding it actually wasn't too long before the motor blew.

-Corey

95_XR7
01-04-2013, 02:06 AM
Well, got the motor out in approx. 6.5hours taking my time. First thing I did is pull spark plugs. Cyl #2 and #3 (pass middle and rear) were both white with oil deposits, as well as cyl #4 (driver front).

When I pulled the heads, everything looked fine. Valves looked brand new on 2, 3, and 4. Well, honestly, everything looked good. I moved onto the oil pan and didn't see anything bad. Well, when inspecting the crank, pistons and rods I happened to notice nice little chunks of the piston skirts on Cyl 3 and 4 were missing.

It took me a few minutes to find all the pieces. Another thing that I noticed is that with 4 of the 6 cylinders, there was excessive side to side play. Motor is junk. :mad: :rolleyes:

-Corey

Scott Long
01-04-2013, 02:28 AM
are the cylinder walls scarred or can you put a couple pistons in this thing and reassemble it?

95_XR7
01-04-2013, 02:33 AM
are the cylinder walls scarred or can you put a couple pistons in this thing and reassemble it?

Cyl 3 is scarred. Head surfaces on the block need refinished due to some scratching.

I was hoping it was just something stupid that I could put the motor back together. But at this rate I'm half tempted to pull this motor and use it to build up a performance motor for my black '95, and just slap a V8 in this car.


Btw, these pistons are cast, which just doesn't make sense to me seeing as how it had an autorotor sitting up top.

-Corey

Scott Long
01-04-2013, 04:10 AM
I thought he had a built lower in that thing?

Well you could put a 5.0L in it and you can get 347 stroker kits pretty cheap for those.

rzimmerl
01-04-2013, 08:14 AM
Btw, these pistons are cast, which just doesn't make sense to me seeing as how it had an autorotor sitting up top.

-Corey

Why would having the AR make any difference on damaging cast pistons? A lot of people have put AR's on top of stock shortblocks, its inevitable of just when they will let go. The pistons survived in mine but bent 4 connecting rods.

95_XR7
01-04-2013, 01:49 PM
Why would having the AR make any difference on damaging cast pistons? A lot of people have put AR's on top of stock shortblocks, its inevitable of just when they will let go. The pistons survived in mine but bent 4 connecting rods.

It's just an insurance thing. If you're going to BUILD up the motor, I don't understand putting in cast pistons when you have the money for an AR.

I still haven't pulled the actual rods and pistons out to see just how damaged they are, or if anything else is jacked up. Heading back to Colorado tomorrow. But at least now I know I need to get in touch with DD.

-Corey

David Neibert
01-04-2013, 04:39 PM
It's just an insurance thing. If you're going to BUILD up the motor, I don't understand putting in cast pistons when you have the money for an AR.

I still haven't pulled the actual rods and pistons out to see just how damaged they are, or if anything else is jacked up. Heading back to Colorado tomorrow. But at least now I know I need to get in touch with DD.

-Corey

Corey,

Sometimes I think it's a case of having the money to either do the AR or a built bottom end, but not both. Once people see a couple other guys getting away with using stock rods and pistons, they think it will be okay for now. Some are probably just waiting until they break the stock stuff before investing in a stronger short block.

David

90sc35thann
01-04-2013, 09:32 PM
Forged is better for higher cylinder pressure however hypereutectic aren't too bad. There are plenty of 5.0 fox body folks running lots of boost on stock bottom ends. Granted hypereutectic pistons are more prone to break under mis-detonation. If you aren't mis-detonating and rattling the tar out of the pistons on the way down in the power stroke they will hold up.

It's like the old 5.0's. People used to beef up the bottom ends with forged rods, forged pistons and steel crankshafts. Little did they know they were throwing their money away. The stock rods, pistons, and crankshafts in those would outlast the cylinder blocks. The stock rotating assembly's were good to about 500-550 HP in those, unfortunately the blocks were not. LOL.

If the engine is tuned properly, a stock rotting assembly will take a beating. If you lean out, etc. something will give. I will typically sacrifice a little power and run on the fat side to save the bottom end and live to race again another day. :-)